(Greek αιών aion) Literally, "a duration of time."
"An interval denoting time." – Theodoret (A.D. 300-400)
In Gnosticism, the Greek term aion refers to a class of being. It can also refer to (sometimes simultaneously):
the title of a Master of the Great Day.
a region or dimension. "The Twelve Aeons or Twelve Cosmic Regions mutually penetrate and co-penetrate without confusion... We must make a clear differentiation between Firmament and Regions. Regions are equivalent to Dimensions. The twelve Aeons are the twelve Regions. The twelve hours of Apollonius are related with the twelve existing Aeons within every Firmament... Unquestionably, the Initiate must work in each one of the Thirteen Aeons, if he wants the Final Liberation. The First Aeon is Malkuth, which is here and in the submerged Abyss. The Second Aeon is Yesod, which is in our sexual organs and in the fourth dimension, within which is the Terrestrial Paradise, the Ethereal World. The Third Aeon is the Astral World, the Sephira Hod. The Fourth Aeon is Netzach, the Mental World. The Fifth Aeon is Tiphereth, the Causal World. The Sixth Aeon is Geburah, the Buddhic or Intuitional World. The Seventh Aeon is the World of Atman, the Ineffable one, the region of Chesed or Gedulah. The Eight Aeon is Binah, the region of the Holy Spirit, the World of Shiva, the Third Logos. The Ninth Aeon is Chokmah, the region of the Logos, the Cosmic Christ. The Tenth Aeon is Kether, the Region of the Ancient of Days. The Eleventh Aeon is the Region of Ain Soph Aur, the Third Great Aspect of the Absolute. The Twelfth Aeon is the region of Ain Soph, the Second Aspect of the Absolute. The Thirteenth Aeon is the region of the Ain, the Unmanifested Absolute. Each one of the Thirteen Aeons must be Self-realized within ourselves. Pistis Sophia must Self-realize herself in these Thirteen Aeons, based on conscious works and voluntary sufferings." - Samael Aun Weor, The Pistis Sophia Unveiled